---
id: 656b47dc2cf39e37025dc033
title: ステップ 13
challengeType: 20
dashedName: step-13
---

# --description--

Reverse the order of the digits in the last four digits of `card_number`, by using a slice with a step of `-1`. You can use either negative or positive indices for the start and end indices.

# --hints--

You could have `card_number_reversed = card_number[-1:-5:-1]` within the `verify_card_number` function. Expected `--fcc-actual--` to equal `--fcc-expected--`.

```js
({
    test: () => {
        const transformedCode = code.replace(/\r/g, "");
        const verify_card_number = __helpers.python.getDef("\n" + transformedCode, "verify_card_number");
        const { function_body, def } = verify_card_number;

        const pyCode = `
card_number = "4111111145551142"
${def}
${function_body.match(/ +/)[0]}return card_number_reversed

verify_card_number(card_number)
`;
        const out = __pyodide.runPython(pyCode, {});
        assert.equal(out, "2411");
    }
})
```

# --seed--

## --seed-contents--

```py
--fcc-editable-region--
def verify_card_number(card_number):
    sum_of_odd_digits = 0
    card_number_reversed = card_number[0:4:2]
    print(card_number_reversed)

--fcc-editable-region--
def main():
    card_number = '4111-1111-4555-1142'
    card_translation = str.maketrans({'-': '', ' ': ''})
    translated_card_number = card_number.translate(card_translation)

    print(translated_card_number)

    verify_card_number(translated_card_number)

main()
```
